[go: up one dir, main page]

US2617037A - Automatic frequency control circuit - Google Patents

Automatic frequency control circuit Download PDF

Info

Publication number
US2617037A
US2617037A US76976A US7697649A US2617037A US 2617037 A US2617037 A US 2617037A US 76976 A US76976 A US 76976A US 7697649 A US7697649 A US 7697649A US 2617037 A US2617037 A US 2617037A
Authority
US
United States
Prior art keywords
frequency
control
voltage
oscillation
transmission
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US76976A
Other languages
English (en)
Inventor
Hugenholtz Eduard Herman
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hartford National Bank and Trust Co
Original Assignee
Hartford National Bank and Trust Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hartford National Bank and Trust Co filed Critical Hartford National Bank and Trust Co
Application granted granted Critical
Publication of US2617037A publication Critical patent/US2617037A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
    • H03L7/00—Automatic control of frequency or phase; Synchronisation
    • H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
    • H03L7/16—Indirect frequency synthesis, i.e. generating a desired one of a number of predetermined frequencies using a frequency- or phase-locked loop
    • H03L7/20—Indirect frequency synthesis, i.e. generating a desired one of a number of predetermined frequencies using a frequency- or phase-locked loop using a harmonic phase-locked loop, i.e. a loop which can be locked to one of a number of harmonically related frequencies applied to it
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/02—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of definite length, i.e. discrete articles
    • B29C41/14—Dipping a core
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
    • H03L7/00—Automatic control of frequency or phase; Synchronisation
    • H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
    • H03L7/08—Details of the phase-locked loop
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
    • H03L7/00—Automatic control of frequency or phase; Synchronisation
    • H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
    • H03L7/08—Details of the phase-locked loop
    • H03L7/10—Details of the phase-locked loop for assuring initial synchronisation or for broadening the capture range
    • H03L7/107—Details of the phase-locked loop for assuring initial synchronisation or for broadening the capture range using a variable transfer function for the loop, e.g. low pass filter having a variable bandwidth
    • H03L7/1075—Details of the phase-locked loop for assuring initial synchronisation or for broadening the capture range using a variable transfer function for the loop, e.g. low pass filter having a variable bandwidth by changing characteristics of the loop filter, e.g. changing the gain, changing the bandwidth

Definitions

  • This invention relates to a circuit-arrangement comprising an oscillatorand provided with means for automatic frequency correction (A. F. C.) of the oscillations produced by the oscillator in accordance with a control-voltage which comprises direct and alternating voltages and is fed through a control-voltage channel to the A. F. C. means.
  • A. F. C. automatic frequency correction
  • control-voltage channel in circuit-arrangements of the aforesaid type is constructed to be such that the ratio between its transmission factors for direct and alternating control-voltages increases with relatively equal, decreasing voltage amplitudes.
  • transmission factor is to be understood to mean the ratio between the output and the input voltages.
  • the control-voltage channel preferably comprises two branches connected in parallel on the input side and which comprise a low-pass filter and a transmission device locking direct voltages respectively, the transmission factor of the latter decreasing with a decrease in alternating input voltage.
  • the reference numeral I designates a triode used as an Oscillator tube, the anode and control-grid of which are connected respectively through coupling condensers, to the ends of a, frequency determining oscillatory circuit 2 comprising a tuning condenser 3 and a coil 4.
  • cathode is earthed through a cathode resistance shunted by a condenser, and a mid-point tapping of coil 4 is likewise earthed.
  • the anode of the triode I is connected, by way of a choke and a resistance-condenser circuit for smoothing purposes, to the positive terminal 5 of a source of anode voltage, the negative terminal 6 of which is earthed.
  • the frequency of the oscillator voltage is stabilized on a, component of a frequency spectrum which is given by a pulse-shaped control-oscillation, of which the fundamental frequency may be appreciably lower (say A to A than the frequency of the stabilized voltage.
  • the oscillator voltage taken from a coupling condenser I is mixed with the control-voltage from a, pulse generator 8 in a, mixing stage 9 constituted, for example, by a hexode mixer tube, of which the output voltage, which constitutes the A. F. C. control-voltage, is passed through a lowpass .filter I0, suppressing the pulse-recurrence freqeuncy.
  • a control voltage is set up, the value and polarity of which vary with the value and polarity of the required frequency-correction; this control-voltage controls a frequency-correction; this cotnrol-voltage controls a, frequency-corrector connected in parallel with the frequency determining oscillatory circuit 2 of the oscillator I to 4.
  • the frequency corrector is constituted by a triode I2 which is coupled back wattless by a condenser l3 and of which the anode is connected, by way of a coupling condenser I4, to the upper end of the oscillatory circuit 2.
  • the reactancetube connection is controlled in such manner that synchronism occurs between the stabilizing component of the control-oscillation and the oscillation produced by the oscillator I to 4. Between the two synchronized oscillations a phase-shift remains, however, the value and polarity of which vary with the value and polarity of the frequency correction produced.
  • the control-voltage is chiefly a direct voltage.
  • interference oscillations may, for example, occur if not only the oscillations from the Oscillator I to 4 and the pulsegenerator 8 occur in the mixer stage 9, but also oscillations of different frequency, alternatively due to parasitic coupling between the controlvolta e channel and other parts of the appara us.
  • the amplitude of the alternating control-voltage occurring when the oscillator oscillation is not yet stabilized by the control-oscillation material ly exceeds the amplitude of alternating interference voltages. It has, for example, been found that with an alternating control-voltage of 6 Vs, the alternating interference voltage amplitude did not exceed 1 V.
  • the control-voltage channel is divided, at the output end of the low-pass filter I0, into two parallel-connected branches, which comprise respectively a low-pass filter I5 having a very small transmission range (for example 5 to 20 c/s) and transmission device which is blocked by a condenser H5 in regard to direct voltages and of which the transmission factor decreases according as the alternating input voltage decreases.
  • a low-pass filter I5 having a very small transmission range (for example 5 to 20 c/s) and transmission device which is blocked by a condenser H5 in regard to direct voltages and of which the transmission factor decreases according as the alternating input voltage decreases.
  • the amplitude-dependent transmission device comprises a theshold device which only transmits the altematingvolta-ges exceeding in amplitude the threshold value given by the threshold device.
  • the threshold device comprises two antiparallel-connected diodes l1, M3, the cathode and the anode being directly interconnected on one side, and being interconnected, through two equal resistances 20' and 20 on the other side.
  • the cathode of the diode I1 is connected through the series-connection of a decoupling circuit constituted by a resistance-condenser circuit and a resistance l9 to the positive terminal 5 of the anode supply and the anode of the diode I 8 'isconnected across a resistance 2! to the negativeterminal.
  • a resistance 22 which is connected to the junction of the resistances 20' and 20" connected between the cathode of diode I1 and the anode of diode 18.
  • the threshold value is on the one hand preferably higher than theamplitude of the most frequent alternating interference voltages and, on the other hand, smaller than the amplitude of the alternating control-voltages, for example or V5 part thereof;
  • a particularly simple threshold device is at tained with the' use of two anti-parallel-connected selenium cells. Naturally, such cells exhibit a threshold value, so that the cells need not be negatively biased.
  • the alternating control-voltage taken from the output of the threshod device brings about a substantial synchronism between the oscillator wave and the stabilizing spectrum component of the control-oscillation.
  • the synchronisation is produced and maintained by an alternating control-voltage of low frequency occurring through a, low-pass filter l5 and by'a-idirect control-voltage.
  • the threshold device alternating interference voltages are materially attenuated or suppressed.
  • the catching range is reduced i. e. the range-in which, with a given tuning of the oscillator, the frequency of the oscillations produced is automatically brought into agreement with a control-frequency differ ent therefrom.
  • a wider catching range could, for example, be achieved by widening'the transmission range of the control-voltage channel and/or by increasing the'mutual conductance of the reactance tube.
  • the two branches of the control-voltage channel are connected in parallel through a coupling condenser 23 at their output end, the junction being connected to an earthed smoothing condenser 24.
  • the control-voltage taken from the two branches controls, through a resistance 25, the reactance tube 12.
  • the amplitude of the alternating voltages, of which the frequency corresponds to or is a harmonic of the pulse recurrence frequency should be lower than the threshold value.
  • the low-pass filter In is connected before the threshold device in the example shown.
  • control-voltages taken from the two branches of the control-voltage channel and comprising direct and alternating voltages may control several frequency-correcting elements of the A. F. 0. means, for example a reactance tube connection and a variable reactance controlled by a motor respectively.
  • the transmission device which is locked in regard to direct voltages, may comprise an amplifier of which the amplification decreases according as the voltage amplitude decreases.
  • I'he characteristic feature is that, if stabilisation of the oscillator-frequency is substantially attained, the transmission range of the controlvoltage channel, fundamentally decreases materially, or, which comes to the same, the time constant of the control-cascade increases.
  • An electrical circuit arrangement for the automatic frequency control of a generated oscillation having frequency deviations about a given central frequency comprising means to generate said oscillation, means to produce a control voltage comprising a direct current component having amplitude variations about a given value proportional tosaid frequency deviations of said oscillation from said given central frequency and an alternating current component having amplitude variations proportional to said frequency deviations of said oscillation from said given central frequency, control voltage transmission means having a first given transmission factor for said direct current component and a second transmission factor for said alternating current component, said second transmission factor being inversely related to the amplitude of said alternating current component, frequency control means coupled to said oscillation generator, and means comprising said control voltage transmission means to apply said control voltage to said frequency control means thereby to suppress said frequency deviations of said oscillation.
  • An electrical circuit arrangement for the automatic frequency control of a generated oscillation having frequency deviations about a given central frequency comprising means to generate said oscillation, means to produce a control voltage comprising a direct current component having amplitude variations about a given value proportional to said frequency deviations of said oscillation from said given central frequency and an alternating current component having amplitude variations proportional to said frequency deviations of said oscillation from said given central frequency, first control, voltage transmission means comprising a low passfilter and having a first given transmission factor for said direct current component, second control voltage transmission means adapted to prevent transmission of direct current coupled in parallel with said first control voltage transmission means and having a second transmission factor for said alternating current component, said second transmission factor being inversely related to the amplitude of said alternating current component, frequency control means coupled to said oscillation generator, and means comprising said first and second control voltage transmission means to apply said control voltage to said frequency control means thereby to suppress said frequency deviations of said oscillation.
  • An electrical circuit arrangement for the automatic frequency control of a generated oscillation having frequency deviations about a given central frequency comprising means to enerate said oscillation, means to produce a control voltage comprising a direct current component having amplitude variations about a given value proportional to said frequency deviations of said oscillation from said given central frequency and an alternating current component having amplitude variations proportional to said frequency deviations of said oscillation from said given central frequency, first control voltage transmission means comprising a low pass filter and having a first given transmission factor for said direct current component, second control voltage transmission means adapted to prevent transmission of direct current and to prevent transmission of alternating current having an amplitude below a given threshold value, said second control voltage transmission means having a second transmission factor for said alternating current component, said second transmission factor being inversely related to the amplitude of said alternating current component, frequency control means coupled to said oscillation generator, and means comprising said first and second control voltage transmission means to apply said control voltage to said frequency control means thereby to suppress said frequency deviations of said oscillation.
  • An electrical circuit arrangement for the automatic frequency control of a generated oscillation having frequency deviations about a given central frequency comprising means to generate said oscillation, means to produce a control voltage comprising a direct current component having amplitude variations about a given value proportional to said frequency deviations of said oscillation from said given central frequency and an alternating current component having amplitude variations proportional to said frequency deviations of said oscillation from said given central frequency, first control voltage transmission means comprising a low pass filter having a first given transmission factor for said direct current component, second control voltage transmission means adapted to prevent transmission of direct current and to prevent transmission of alternating current having an amplitude below a given threshold value, said second control voltage transmission means comprising a pair of oppositely poled negatively biased diodes and having a second transmission factor for said alternating current component, said second transmission factor being inversely related to the amplitude of said alternating current component, frequency control means coupled to said oscillation generator, and means comprising said first and second control voltage transmission means to apply said control voltage to said frequency control means thereby to suppress said
  • An electrical circuit arrangement for the automatic frequency control of a generated oscillation having frequency deviations about a given central frequency comprising means to generate said oscillation, means to produce a control voltage comprising a direct current component having amplitude variations about a given value proportional to said frequency deviations of said oscillation from said given central frequency and an alternating current component having amplitude variations proportional to said frequency deviations of said oscillation from said given central frequency, said control voltage producing means comprising a source of periodic voltage pulses having a fundamental frequency harmonically related to said given central frequency and means to mix said generated oscillation and said periodic voltage pulses to produce said control voltage, first control voltage transmission means comprising a low pass filter and having a first iven transmission factor for said direct current component, second control voltage transmission means adapted to prevent transmission of direct current coupled in parallel with said first control voltage transmission means and having a second transmission factor for said alternating current component, said second transmission factor being inversely related to the amplitude of said alternating current component, frequency control means coupled to said oscillation generator, and means comprising said first and
  • An electrical circuit arrangement for the automatic frequency control of a generated oscilliation having frequency deviations about a given central frequency comprising means to generate said oscillation, means to produce a control voltage comprising a direct current component having polarity and amplitude variations about a given value proportional to said frequency deviations of said oscillation from said given central frequency, said control voltage producing means comprising a source of periodic voltage pulses having a fundamental frequency harmonically related to said given central frequency and materially lower than said given central frequency, means to mix said generated oscillation and said periodic voltage pulses to produce said control voltage and a first low pass filter adapted to suppress the pulse recurrence frequency of said periodic voltage pulses, first control voltage transmission means comprising a second low pass filter and having a first given transmission factor for said direct current component, second control voltage transmission means adapted to prevent transmission of direct current coupled in parallel with said first control voltage transmission means and having a second transmission factor for said alternating current component, said second transmission factor being inversely related to the amplitude of said alternating current component, frequency control means coupled to

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
  • Ac-Ac Conversion (AREA)
US76976A 1948-03-27 1949-02-17 Automatic frequency control circuit Expired - Lifetime US2617037A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL673839X 1948-03-27

Publications (1)

Publication Number Publication Date
US2617037A true US2617037A (en) 1952-11-04

Family

ID=19802214

Family Applications (1)

Application Number Title Priority Date Filing Date
US76976A Expired - Lifetime US2617037A (en) 1948-03-27 1949-02-17 Automatic frequency control circuit

Country Status (6)

Country Link
US (1) US2617037A (da)
BE (1) BE488124A (da)
DE (1) DE808961C (da)
FR (1) FR983711A (da)
GB (2) GB673839A (da)
NL (1) NL85185C (da)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2752497A (en) * 1949-11-08 1956-06-26 Hartford Nat Bank & Trust Co Developing electrical oscillation
US2775703A (en) * 1952-05-17 1956-12-25 Hartford Nat Bank & Trust Co Circuit-arrangement comprising a frequency-stabilized oscillator
US2801282A (en) * 1951-11-30 1957-07-30 Rca Corp Oscillator synchronizing circuit
US2930892A (en) * 1954-03-26 1960-03-29 Sperry Rand Corp Demodulator for a phase or frequency modulated signal
US2932793A (en) * 1956-11-20 1960-04-12 Marconi Wireless Telegraph Co Automatic frequency controlling systems
US2987679A (en) * 1957-11-13 1961-06-06 Rca Corp Automatic gain control circuit
US3041545A (en) * 1957-10-29 1962-06-26 Itt Time sensitivity variable gain amplifier
US3316497A (en) * 1965-07-09 1967-04-25 Robert R Brooks Phase controlled oscillator loop with variable passband filter
US3327245A (en) * 1963-09-30 1967-06-20 Alfred Electronics Means and method for stabilizing negative feedback systems
US3363194A (en) * 1965-05-24 1968-01-09 Sylvania Electric Prod Phase lock loop with extended capture range
US3993958A (en) * 1975-08-20 1976-11-23 Rca Corporation Fast acquisition circuit for a phase locked loop

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1168480B (de) * 1952-12-31 1964-04-23 Gasaccumulator Svenska Ab Synchronisiereinrichtung, insbesondere fuer Fernsehempfaenger
BE562554A (da) * 1956-11-20
DE1147257B (de) * 1959-09-17 1963-04-18 Blaupunkt Werke Gmbh Fernsehempfaenger mit einem nachstimm-baren Zeilenoszillator
DE1114531B (de) * 1959-10-07 1961-10-05 Blaupunkt Werke Gmbh Fernsehempfaenger mit einem sich selbsttaetig nachstimmenden Zeilenoszillator

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2406309A (en) * 1942-11-03 1946-08-20 Hartford Nat Bank & Trust Co Frequency stabilization

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2406309A (en) * 1942-11-03 1946-08-20 Hartford Nat Bank & Trust Co Frequency stabilization

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2752497A (en) * 1949-11-08 1956-06-26 Hartford Nat Bank & Trust Co Developing electrical oscillation
US2801282A (en) * 1951-11-30 1957-07-30 Rca Corp Oscillator synchronizing circuit
US2775703A (en) * 1952-05-17 1956-12-25 Hartford Nat Bank & Trust Co Circuit-arrangement comprising a frequency-stabilized oscillator
US2930892A (en) * 1954-03-26 1960-03-29 Sperry Rand Corp Demodulator for a phase or frequency modulated signal
US2932793A (en) * 1956-11-20 1960-04-12 Marconi Wireless Telegraph Co Automatic frequency controlling systems
US3041545A (en) * 1957-10-29 1962-06-26 Itt Time sensitivity variable gain amplifier
US2987679A (en) * 1957-11-13 1961-06-06 Rca Corp Automatic gain control circuit
US3327245A (en) * 1963-09-30 1967-06-20 Alfred Electronics Means and method for stabilizing negative feedback systems
US3363194A (en) * 1965-05-24 1968-01-09 Sylvania Electric Prod Phase lock loop with extended capture range
US3316497A (en) * 1965-07-09 1967-04-25 Robert R Brooks Phase controlled oscillator loop with variable passband filter
US3993958A (en) * 1975-08-20 1976-11-23 Rca Corporation Fast acquisition circuit for a phase locked loop

Also Published As

Publication number Publication date
FR983711A (fr) 1951-06-27
GB688798A (en) 1953-03-11
BE488124A (da)
NL85185C (da)
DE808961C (de) 1951-07-23
GB673839A (en) 1952-06-11

Similar Documents

Publication Publication Date Title
US2617037A (en) Automatic frequency control circuit
US2406309A (en) Frequency stabilization
US2624006A (en) Automatic frequency control circuit
US2574482A (en) Automatic frequency and phase control system
US2540333A (en) Device for automatic frequency correction
US2231704A (en) Homodyne receiver
US2786140A (en) Apparatus for frequency interpolation
US2662181A (en) Automatic-frequency control apparatus for maintaining a predetermined-frequency difference between two waves
US2349811A (en) Reactance tube modulation
US2676262A (en) Automatic frequency control system for oscillators
US2197900A (en) Fading regulation in television receivers
US2752497A (en) Developing electrical oscillation
GB1019336A (en) Self-tuning radio receivers
US2531301A (en) Circuit arrangement for frequency controls
US2764681A (en) Frequency stabilized and controlled oscillatory system
US2339608A (en) Frequency modulation system
US2798946A (en) Automatic frequency control system which stops hunting when in tune
US3046496A (en) Stabilized frequency modulated oscillator
US2775703A (en) Circuit-arrangement comprising a frequency-stabilized oscillator
US3227967A (en) Arrangement for the electronically controllable wobbling of an oscillatory circuit
US2719231A (en) Oscillator frequency control
US2445662A (en) Frequency modulation system
USRE22834E (en) Frequency modulation system
US2760072A (en) Automatic frequency stabilisation
US2467345A (en) Automatic frequency control system